Reaction product of a polyspirane resin with a polycarboxylic acid anhydride, mixtures thereof with other polymeric materials, process for preparing same, and conductor coated therewith



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Patented Jan. 2, 1962 3 015 643 REACTION PRODUCT OF A POLYSPIRANE RESIN WITH A POLYCARBOXYLIC ACID ANHYDRIDE, MIXTURES THEREOF WITH OTHER POLY- where R is taken from the group consisting of hydrogen and methyl groups, R is taken from the group consisting of the aliphatic hydrocarbons defined by (CHQ where S is an integer from -8 and alicyclic and aromatic MERIC MATERIALS, PROCESS FGR PREPARIN 5 hydrocarbons of 5-6 carbon atoms and derivatives therei AND CQNDUCTOR COATED THERE- of, X-l-Y is equal to an intege; frojtgqZ tgOOyandT 1:! Is an integer equa to no more t an 0 o p c ggghg ggg ggz ggg acceptable molecular weight range for this invention is to Shawinigan Resins Corporation, Springfield, Mass :1 4OO ZOGOO' corporation of Massachusetts The class of organic acid anhydride materials that is No Drawing. Filed Aug. 11, 1958, se N 754,173 useful in the present invention for reaction with the poly- 28 Claims. (Cl. 260-42) spirane resins is very broad and includes both substituted and unsubstituted polycarboxylic acid anhydrides and g igi ggg .g a i atnprgamc resin those polymers comprising polymeric polyanhydrides. ca y 1 mm a novel f i The reason for the suitability of such a broad class of i i compilsmg mgdlfied polysplmne composition materials is believed to be the dual function of a polywhich is particularly suitable for electrical conductor carboxvfic acid anhydridg materia in the resin, namely, igi i gf g gigi3 of maiufacigre such i that of a catalyst in promoting the direct reaction of acthis insulafi m ateri 2 3 sue con ucmrs havmg tive groups available in the resin as Well as that of chem- It has b H k 1 ically reacting with the polyspirane resin. The particu- We sown in me to appy resm coat' lar reaction which modifies the polyspirane resin and {figs toplecmcal conductors for Purpose of electrically ther by mal es it useful for the obiects of this invention msulaimg f conquctor .from us surroundings Both is cdmmonly known in the art as the cure reaction and orgamg and Inorganic coating materials have 'i used results in a substantially crosslinked product. The scope T i up 3 silch factors asdtemperature :servlce of the class of acid anhydride materials suitable for re- 1 at P fins exposure.an the nlichamcal i action with a polyspirane resin will be more clearly delations which the coated wire must withstand either in fined in the sucwedzn exam les and in Subsequent di the fabrication of the electrical device or its subsequent cussions thereon gg i anhydride matef The P Physical and rials will furthermore be referred to as curing agents ties which the insulation in the present application poshereinafter for ease of refinance sesses are substantially superior heat stability, cut-thru The addition of Ether polymegmaterials to polyspiranes tiamperaiure and re.s1S.tance' p a p containin polyfunctional or auic acid anhydrides imtion of improved properties in insulation is certainly surproves cecrtain P y and echemical properties of the f as resin product dependent largely upon the composition of pnmilry opject of i mvemlon Is the provlslon the particular polyme added Although only certain an orgamc r6811? compoltlcn particularly Suitable for phenolic resins epory iesins and polyurethanes were used i enamel coatings havmg Suitable stability i in combination with the modified polyspirane composigf z g 22 52% fii gi g .2 tions, it is believed that other resin additives and combie i W a nations thereof would also be suitable to enhance certain peratures mamtams its characteristic of being continuous, 40 desirable properties The effect of some of the various l lie slii tit s i ihis i n nt i ii ciih be accompl shed by polymer additives physical {and Phemical properties using as the resin composition a modified polyspirane resg iz W111 be descnbed m the followmg exiqgomprisling i f i i f .1; a pg i resin 'i he invention is practiced in a specific embodiment as W1 a po ycar oxy 1c am an y r1 e e1t er a one or in combination with other polymers in order to impart igs g m the followmg examples but 18 not l'lmlted certaii sipeciald chemical and physical properties which EXAMPLEI may e esire The term anhydride as used in this description of the Preparation of the H (glmFrdiyll-dene invention includes both the acid anhydrides of aliphatic 5o Pemaerythnwl) resm and cyclic polycarboxylic acids as well as the acid di- 480 gms. of technical pentaerythritol, which is a mixanhydrides of polycarboxylic acid compounds containture of 88 parts by weight of the mixture of monopentaing more than two carboxyl groups. The anhydride erythritol and 12 parts of dipentaerythritol is charged compounds that are useful in the practice of this invento a 5-liter flask equipped with a reflux column along tion are not limited merely to the anhydrides of organic with 1384 gms. of a 24% by Weight aqueous solution acids in the sense that certain polvmeric materials conof glutaraldehyde having a pH between 25-4 and in taining anhydride groups are also suitable. addition, 1200 gms. of distilled water. The mixture is The reaction product of a polyspirane with the type heated to refiux and the contents stirred, by which time of acid anhvdride material mentioned possesses the very the technical pentaerythritol has all dissolved. The catadesirable properties which makes it an excellent dieleclyst 7.4 gms. of oxalic acid, a water soluble organic trio, and it can be produced in film fo m without the aid acid. is added to the boiling solution. Within a period of other polymer materials. The addition of other polyof five minutes after the addition of the acid catalyst, mers can improve certain of these properties, however, insoluble resin particles have already formed. The reas Will be shown in later examples. action is substantially completed within two hours. The The particular polyspirane resin that is acceptable in resin is then filtered. washed with water until neutralized, the practice of this invention can be represented by the and dried. The resin is a white powder with a melting following general formula: point of at least 200 C.

/OCE2 OH:O F /O-C\1E2 CE2OC CHz-O\ C R-o-R' CR /C RCR CH2 \CH2 J i Y OH OH The quantitative analysis for the carbon, hydrogen and oxygen content of the compound yielded 58.4%, 8.2%, and 35.4% respectively, which is in close agreement with the theoretical values for the compound.

Preparation of the wire enamel For the preparation of a wire enamel the following procedure is used:

Into a 2-litcr, round-bottomed flask equipped with a stainless steel condenser and a motor driven stirrer is placed 488 ml. of cresylic acid and 155 ml. of naphtha. To the solvent mixture is added 150 gms. of poly(glutardiylidene pentaerythritol). The contents are then stirred, heated to 50100 C., and held in that temperature range for approximately 15 minutes, at which time the heating is discontinued. 7.5 gms. of pyromellitic dianhydride, the curing agent, are added directly to the resin batch with continued stirring. After solution of the curing agent the stirring is discontinued and the hot resin solution is then filtered through a Buchner funnel lined with felt and into the final enamel container.

The wire enamel prepared in Example 1 was applied to No. 18 magnet wire and subjected to the standard tests of acceptance for this application. The wire enamel was applied to the wire and cured with heat by conventional means. The following data in Table I represents the comparative results of thermal properties tests between the polyspirane coating and a coating of polyvinyl formal phenolic resin applied to the same size Wire in the same The 1 kv.-life tests were made in accordance with the provisions of the A.I.E.E. (American Institute of Electrical Engineers) specifications No. 57, dated October, 1955, and the test is a measure of the period for which a coating can be exposed at the particular temperature indicated before it will fail as electrical insulation upon the application of 1000 volts to the sample.

The cut-thru temperature is also an A.I.E.E. test for thermal plastic flow whereby crossed coated wires are mechanically loaded While the ambient temperature is raised until electrical contact is made between the metallic substrates of the wires. The flexible life is a modified A.S.A. (American Standards Association) test whereby the embrittlement characteristics of the coating are measured by exposure to elevated temperatures by wrapping around a circular mandrel. It can be observed from the data in Table I that the polyspirane resin performance was superior to the polyvinyl formal-phenolic resin in all thermal properties.

The above cured polyspirane coating possessed excellent resistance to the action of the usual solvents utilized to test the chemical stability of an electrical insulating film. When the film was subjected to a 16 hour immersion in liquified monochlorodifiuoromethane, no blisters were found and the weight percent of the film extracted was exceptionally low. Immersion of the film in both boiling methanol and boiling toluene for a period of two hours in each of the liquids resulted in very low weight percent extractibles.

EXAMPLE 2 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel, except that in the latter preparation 6 ml. of an 84% by weight solution of zinc naphthenate in a hydrocarbon solvent is added to the cooled enamel batch after the filtration step.

Wire samples made up of the heat cured product from the above batch in contrast to like samples made up from a batch containing the same amount of pyromellitic dianhydride but not containing the zinc naphthenate had a cut-thru temperature of 300 C. in comparison to 270 C. for the latter. The zinc naphthenate additive also raised the abrasion resistance from 30 strokes to 60 strokes and promoted a faster rate of cure for the resin film.

EXAMPLE 3 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that in the latter preparation in substitution for the pyromellitic dianhydride, 7.5 gms. of maleic anhydride is used and 3 gms. of salt-free poly (tetrafiuoroethylene) as a 65% by weight aqueous dispersion is added to the cooling resin batch after the pyromellitic dianhydride addition. The poly(tetrafiuoroethylene) is added while stirring the enamel batch.

EXAMPLE 4 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that in substitution for the polyspirane resin prepared in the manner heretofore described, gms. of poly(glutardiylidene pentaerythritcl) prepared with a nonionic emulsifier and a different polymerization catalyst is used.

The preparation of the po1y(glutardiylidene pentaerythritol) used in the present example is as follows:

1176 gms. of glutaraldehyde, a 25% aqueous solution having a pH of 4.0, is reacted with 423 gms. of a mixture of pentaerythritols, the mixture containing 88% by weight of the mixture of monopentaerythritol and 12% of dipentaerythritol. The glutaraldehyde pentaerythritol mixture is added to 2040 ml. of distilled water and the contents heated to reflux in the presence of 35.9 gms. of a nonionic emulsifier, consisting of a copolymer of ethylene oxide and propylene oxide. 12.2 gms. of hydrogen lauryl sulfate catalyst is added to initiate the reaction after reflux is achieved. The resin is then filtered, washed with water until neutralized, and dried. The resin is a white powder with a melting point of at least 250 C.

EXAMPLE 5 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that in substitution for the polyspirane resins prepared in the manner heretofore described, 150 gms. of poly(malondiylidene pentaerythritol) prepared in the following in the following manner is used:

Into a 5-liter, 3-neck, round-bottomed flask equipped with a motor driven stirrer, dropping funnel and stillhead, thermometer and connecting condenser gms. of pentaerythritol is added, followed by 932 gms. of dry benzene. Next 256 gms. of the triethylmonomethyl diacetal of malonaldehyde is added to the reaction mixture followed by 4.2 gms. of p-toluenesulfonic acid. The reaction mixture is heated in a water bath maintained at 80-85 C. for approximately 2 hours until substantially all of the alcohol-benzene azeotrope with a boiling range of 5572 C. has been distilled off. At this time 1745 gms. of cresylic acid is added to the reaction mixture along with a further 8.4 gms. of p-toluenesulfonic acid. The reaction mixture is then stirred at 80-90 C. until substantially all of the benzene-alcohol remaining in the reaction mixture is distilled 01f. A slight vacuum will aid distillation. The reaction mixture is then cooled, neutralized, diluted with 4 liters of water, and filtered for the isolation of the resin product. The resin after drying is gogr ean colored powder with a melting point of at least EXAMPLE 6 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that in substitution for polyglutardiylidene pentaerythritol) 150 gms. of poly(terephthaldiylidene pentaerythritol) prepared in the following manner is used:

Into a 3-liter, 3-necked, round-bottomed flask equipped with a reflux column is charged 158 gms. of pentaerythritol along with 780 gms. of a 20% by weight solution of terephthaldehyde in hot water and an additional 600 gms. of water. The mixture is heated to reflux and the contents stirred, by which time the pentaerythritol has all dissolved. The catalyst 2.7 gms. of phosphoric acid, a water soluble inorganic acid, is added to the boiling solution. The reaction is substantially completed within two hours. The resin is then filtered, washed with water until neutralized, and dried. The resin is a white powder with a melting point of at least 300 C.

EXAMPLE 7 The same procedure is followed as described in Example l for both the preparation of the polyspirane resin and the wire enamel except that in substitution for the poly(glutardiylidene pentaerythritol), 150 of poly- (succindiylidene pentaerythritol) prepared in the following manner is used:

Into a 3-liter, 3-necked, round-bottomed flask equipped with a reflux column is charged 157 gms. of pentaerythritol along with 495 gms. of a 20% solution by weight of succinaldehyde in water and an additional 500 gms. of water. The mixture is heated to reflux and the contents stirred, by which time the pentaerythritol has dissolved. The catalyst 0.8 gm. of formic acid, a Water soluble organic acid, is added to the boiling solution. The reaction is substantially completed within two hours. The resin is then filtered, washed with water until neutralized, and dried. The resin is a white powder with a melting point of at least 240 C.

EXAMPLE 8 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that in substitution for the poly(glutardiylidene pentaerythritol), 150 gms. of the copolymer product of equimolar portions of glutaraldehyde and 3-methyl glutaraldehyde and the pentaerythritol mixture is used. Also in substitution for the 488 ml. of cresylic acid and 155 ml. of naphtha used in that example, 214 ml. of cresylic acid and 429 ml. of naphtha are used in the preparation of the wire enamel.

EXAMPLE 9 The same procedure is followed as described in Example 2 for both the preparation of the polyspirane resin and the wire enamel except that in the latter preparation, 30 gms. of the phenol adduct of the reaction product between 1 mol of trimethylolpropane and 3 mols of tolylene diisocyanate is added to the cooling enamel batch following the pyromellitic dianhydride addition and before the filtration steps shown therein. The polyurethane is dissolved in a 50% by weight solution of equal portions of cresylic acid and naphtha before the addition to the enamel batch and is added to the latter with some stirring.

Wire samples made up of the heat cured product from the above batch in contrast to like samples made up from a batch containing the pyromellitic dianhydride but not containing the polyurethane had a wet dielectric strength of 2400 volts/mil in comparison to 1700 volts/mil for thelatter.

EXAMPLE 10 The same procedure is followed as described in Example 2 for both the preparation of the polyspirane resin and the wire enamel except that in the latter preparation, 15 gms. of a meta-para-cresol-formaldehyde condensation product is added to the cooling enamel batch with some stirring following the pyrornellitic dianhydride addition and before the filtration steps shown therein.

Wire samples made up of the heat cured product from the above batch in contrast to like samples made up from a batch containing pyromellitic dianhydride but not containing the meta-para-cresol-formaldehyde condensate had a 1 kv.-life at 240 C. of 1 0 hrs. in comparison to hrs. for the latter.

EXAMPLE 11 The same procedure is followed as described in Example 2 for both the preparation of the polyspirane resin and the wire enamel except that in the latter preparation, 15 gms. of pyromellitic dianhydride is substituted for the 7.5 gms. used in Example 1 and 50 gms. of hisphenol A-epicholorhydrin epoxy resin is added to the batch with some stirring thereafter but before the filtration step.

Wire samples made up of the heat cured product from the above batch in contrast to like samples made up from a batch containing the same amount of pyromellitic dianhydride but not containing an epoxy resin had a wet dielectric strength of 3480 volts/mil in comparison to 1600 volts/mil for the latter.

EXAMPLE 12 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the latter preparation, 7.5 gms. of phthalic anhydride is substituted for the 7.5 gms. of pyrornellitic dianhydride used in that example.

EXAMPLE 13 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the latter preparation, 3.0 gms. of methyl succinic anhydride is substituted for the 7.5 gms. of pyromellitic dianhydride used in that example.

EXAMPLE 14 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the latter preparation, 7.5 gms. of succinic anhydride is substituted for the 7.5 gms. of pyromellitic dianhydride used in that example.

EXAMPLE 15 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enlmel except that with the latter preparation, 5.0 gms. of the copolymer of the 1:1 molar ratio of vinyl acetate and maleic anhydride is substituted for the 7.5 gms. of pyromellitic dianhydride used in that example.

EXAMPLE 16 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the latter preparation, 7.5 gms. of the copolymer of the 1: 1 molar ratio of styrene and maleic anhydride is substituted for the 7.5 gms. of pyromellitic dianhydride used in that example.

EXAMPLE 17 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the litter preparation, 15.2 gms. of hexahydrophthalic anhydride is substituted for the 7.5 gms. of pyromellitic dianhydride used in that example.

EXAMPLE 18 The same procedure is followed as described in Example 1 for both the preparation of the polyspirane resin and the wire enamel except that with the latter preparation, 7.5 gms. of hexachloroendomethylenetetrahydrophthalic amples of (a) above include succinic anhydride and maleic anhydride is substituted for the 7.5 gms. of pyromellitic tall oil acids, 2-ethylhexoic acid and fatty acids. Suitdianhydride used inthat example. able examples of the promoters, in addition to the zinc Other polyspiranes are suitable for the practice of this naphthenate used in Example 2, are available commerinvention than those specifically shown in the examples cially and include cobalt naphthenate and manganese and whose formulations will be obvious to the man skilled 5 tallate. in the art after the following discussion. The dialdehyde The preferred range of concentration of the organic component of the resin can be selected from the group curing agent in the final resin product is 1-10% although Consisting of succiflaldehyde, hyde and mixcompositions containing up to about 25% of this matetllres thereof, Subefic dialdehyde, aZlaic dialdehyde, rial are permissible in electrical insulation applications, Sebacic dialdehyde and mixtures therfiof, y p above which concentration for the types of acidic curing tanfidial, cycloheXafledial, Phthfllic aldehydfiS and mixtures agents shown, the dielectric properties of the resin prodthereof, mixtures of and methyl and not fall ofi sharply. It is obvious that mixtures of the ethyl diacetals of mfilflflaldehyde, succiflaldehyde and acid anhydride curing agent materials described heretoghltafaldehydfi, mfithyl and ethyl diketals 0f -P fore are suitable for the practice of this invention. diOfie, 2,5-11eXaI1edi0I1e and 2,6-hePta11edi0I1e, and 15 As was disclosed in the preceding examples, certain of lures therfiof, and methyl and ethyl Substituted P the physical properties of the heat-cured polyspirane resin llcts Of and Th6 pentael'ythritol Component P films were improved by the addition to the wire enamel the P y p cfmdensafion Product can be a materlal of other polymeric materials. The specific polymers taken from p consisting of monopemael'ythnwl added were selected from the group consisting of polyisoand mixtures of monopentaerythritol with dipentaerythricyanates, Phenolic resins and epoxy resins m1 coPtflifliflg P 50% diPelzltiielyihflto1 by welglflt of Other polyisocyanates are also suitable for the practice the mlXtufe- Acld catalysts Suitable the polyspll'ane of this invention as substitutes for the particular one used reaction can be either inorganic acids such as hydroin Example They can be limited generally t0 those chlm'icqsulfm'ic and phosplloric acids Q Organic types Suc h having two or more isocyanate groups either none or all 35 P' Q l W 'f acldsacid of which reactive groups being blocked or hindered from concemmfien 15 net cmlcal during the polymenzatlon immediate reaction by a previous reaction with a phenolic The Preferred concgmrafion of the PolYsPimne type modifier. The blocked isocyanates useful in this resin in the reaction products of this invention is about invention are polyurethanes which on heating f 0 5099% y Welght- 250 C. yield a polyisocyanate. Other suitable polyiso- TheclassPo1ycarboxyhcac1dailhydndacunngagems cyanates include compounds such as phenylene diiso- Yvhich are smtable for the pmysplfanes of the Present cyanates, tolylene diisocyanates, naphthalene diisocymvenflon a wry 1arge P and Includes (a) Polycar anates, diphenylmethane diisocyanates, cyclohcxane diol Q acld anhydndss OI h saturated e diisocyanates, ethylene diisocyanates, tetrarnethylene diahljhanc Semis i afomauc liolycarboxyhc.aud anhy' isocyanates, hexamethylene diisocyanates, methyibenzene dudes (c) ahcychc acld anhydndas 4 subsntuted Prod triisocyanates, polyisocyanates which are the partial reucts of (a), (b) and and (9) mixtures of (a), (1,) action product of diisocyanates with polyhydric alcohols,

(c) and (d). A limitation on the suitability of a material and the like and mixtures thereof from the ablwe class in,the practice of this i for The phenolic resins which are useful in the present i preparation. of a sqlvem systfzm of Wm: enamel invention can be limited to those soluble in the solvent sysi the Particular and anhydnde cmmg agen? be Solu' 4o tems employed for the preparation of the wire enamels. we m tha solvent of the enamel system Stumble Such can readily be selected from the general class of phenolic aldehyde resins.

The phenolic portion of the resin in addition to the meta-para-cresol used in Example 10 may also be selected from the group consisting of xylenols, mixtures of phenol and cresol, and wood oil phenolic bodies, petroalkyl phenols, coal-tar phenol and others. The aldehyde portion of the resin in addition to the formaldehyde used in Example 10 may also be para'formaldehyde or other suitable aldehydes. The preferred composition of phenolic-aldehyde resin useful in this invention is obtained Certain chemical compounds are usgful additives to by reacting one mol of the phenolic compound with 0.7

the polyspirane cure reaction system as promoters of the to mols of f suitilbl'i aldehydecure reaction. These promoters increase the rate of cure 55 Th6 P Y T651115 which are Preferred 111 the Practlce 0f anhydride. Suitable examples of (b) above include pyromellitic dianhydride and phthalic anhydride. A suitable example of (0) above includes hexanhydrophthalic anhydride. Suitable examples of (d) include hexachloroendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, methyl succinic anhydride and endomethylenetetrahydrophthalic anhydride.

The class of polymeric curing agents suitable for the practice of this invention includes copolymers of styrenemaleic anhydride and vinyl acetate-maleic anhydride.

and thereby reduce the time needed for the cure reaction the present invention are those which can be represented as well as improve certain properties of the cured resinous by the following general formula:

H H H X H H H X H H H ""Q'Q @Q HC-CO-O C OCCCO O O--CCCH o it i sin til. i ii 0 product. The class of chemical compounds useful as where X and Y are taken from the group consisting of promoters of the polyspirane cure reaction in addition to hydrogen, methyl groups and aliphatic and aromatic hythe organic curing agents is a metallic salt of certain ordrocarbons and N is an integer from O to 10. It is beganic acids, which salt is also soluble in the liquid wire lieved that non-resinous epoxy and poly-epoxy compounds enamel system. The class of useful materials as promotare utilizable in this invention as well as other polymeric ers for the cure reaction can be further classified as resin materials generally. driers or metal soaps which terms are in common usage Both ionic and nonionic emulsifiers are suitable for the in the art. 7 preparation of the polyspirane resin. The purpose of the The metallic portions of the salt can be selected from emulsifier in the resin preparation is to increase the mothe group consisting of lead, cobalt, manganese, calcium, lecular weight of the resin by keeping it in contact with zinc, iron and cerium. The acid portion of the salt can the reaction medium for a longer period of time than be selected from thegroup consisting of naphthenic acid, 76 would ordinarily occur due to the general insolubility of the resin in an aqueous system. Suitable ionic emulsifiers would be sodium lauryl sulfate and dicocodimethylammoniumchloride; The emulsifier is useful, in the preparation in a weight range of 0.140% of the combined weight of the aldehyde and pentaarythritol mixture used in the resin.

The naptha used in the preparation of the wire enamels is an aromatic liquid hydrocarbon of boiling range 150- 184" 0., derived from coal tar and/orpetroleum. Other liquids which are suitable as diluents for the cresylic acid in the preparation of the wire enamels in this application are substituted and unsubstituted aromatic liquid hydrocarbons such as chlorobenzene, toluene and cumene, and such other solvents as furfuryl alcohol and furfural. The acceptable total solids range for wire enamels in this invention is to 40 weight percent total solids.

The cresylic acid that is useful in the wire enamel preparation is a liquid phenolic compound consisting of primarily xylenols and cresols and having a boiling range of 195-227 C.

The poly(tetrafiuoroethylene) used in Example 3 is commercially available. Suitable substitutes for this material in the practice of the invention are the polymers of ethylene and the halogenated derivative thereof. The presence of 0.5-5% by weight of these additives in the solid resinous product improves the abrasion resistance of films made therefrom.

The curing temperature required to obtain a continuous hard film for a polycarboxylic acid anhydride cured polyspirane system not containing solvents or other additives is generally limited to a temperature above the melting point of the particular resin used. At this temperature the acid anhydride material will have already catalyzed the cure reaction of the resin and have become a portion of the cured product. But at higher concentrations of a curing agent having a melting pointlower than the particular polyspirane used it ,is possible that the melting point of the polyspirane will be lowered thereby and a cure effected at a temperature below the melting point of the polyspirane itself.

The coating compositions used in the preceding examples impose other limitations upon the curing temperature of the final resin product dependent upon such factors as the relative volatility of the particular solvent used and the reactivity of any other particular additive. 45 the general formula Such other commercial factors as the type curing equipment to be used and the desired time to complete the cure reaction will also influence the cure temperature selected. For the compositions in the preceding examples a standard commercial type wire enamel towe was utilized, wherein operating temperatures of 300C. to 400 C. were employed.

The exact curing temperatures of the above cured crosslinked films themselves were not determined during the wire tower runs. Even though the curing step was found to be a critical factor in producing good films, obtaining these temperatures is extremely diflicult to do in such an apparatus because of the continuous travel of the coated wire through the tower during the curing process. Curing temperatures were obtained, however, for films of the composition disclosed in Example 1 which films were 0.001- 0005 of an inch thickness in air circulated oven for various curing periods and the properties of the cured films determined. Such films cured at 240 C. for periodsof /2, 1, 2, 3, 4, and 5 hours did not have the flexibility of fully cured polyspirane systems. When the cure-temperature was raised to 300 C., however, the films cured for a minute period gave'the acceptable flexibility and solvent resistance noted above. It is not intended to limit the curing temperature of the films in the present invention to a minimum of 300 C. by the above discussion, but rather to say that the cure temperature is greater than 240 C. It is also obvious from the above discussionthat both the proper cure temperature and time of cure can be determined experimentally for the particular polyspirane system employed.

It is to be understood that this invention is not limited to the particular wire coating or wire size described above. It is obvious from the, above test results that a wire coated with the polycarboxylic acid anhydride cured polyspirane enamel alone will be acceptable as class C. (F) service wire and higher. But it is also obvious to the man skilled in the art to modify the application of the enamel so as to upgrade its high temperature usefulness by means of known practices in the field. It is possible for instance to utilize the present coating as an undercoat on a Wire to apply as an overcoat one or more of the many compatible insulating varnishes and thereby obtain a coating acceptable at even higher operating temperatures. It is also not intended to limit the application of the resin as an electrical insulation for wire merely. It is possible by means of extrusion, dipping, casting and other known means to form insulation from this material that is useful in such electrical applications as slot liners, encapsulation, sheet insulation, and surface coatings. The resin can also be used as an adhesive agent in the bonding of electrical parts that expect use at elevated temperatures. Fu ther use can be made of the invention as insulation and/or impregnating varnishes for such articles as glass tapes and electrical coils. Other non-electrical uses of this resin are ap parent where chemical resistance and temperature stability of the final product are needed, such as surface coatings and others.

In addition to the various applications for which this resin is particularly suitable as hereinhefore described, it will be obvious to the man'skilled in the art that not only other applications are apparent but that other compositions or other processes for the manufacture of those compositions are likewise Within the scope of this invention.

What is claimed is:

1. A composition of matter comprising the crosslinked insoluble reaction product of a polyspirane resin having where R is taken from the group consisting of H and CH R is taken from the group consisting of aliphatic hydrocarbons defined by CH wheres is an integer from 08 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted products thereof, X plus Y is equal to an integer from 2-10() and Y is equal to no more than 50% of X plus Y with an organic material selected from the group consisting of (a) polycarboxylic acid anhydrides of thesaturated and unsaturated aliphatic series, (b) aromatic polycarboxylic .acid anhydrides, (c) alicyclic polycarboxylic acid an- 11 organic material is a polymeric polyanhydride selected from the group consisting of styrene-maleic anhydride and vinyl acetate-maleic anhydride.

5. A composition of matter as in claim 1 wherein the 12 which reaction product also containing 1.0 to percent by weight of a cure promoter.

12. A composition of matter as in claim 1 wherein the reaction product contains'in parts by weight about organic material is an alicyclic polycarboxylic acid an- 5 75-99 parts of the polyspirane and about lparts of hydride. 7 the organic material.

6. A composition of matter as in claim 1 wherein the 13. A composition of matter as in claim 12 wherein polyspirane resin comprises poly(glutardiylidene pentathe solid resinous product contains about 0.5-5% of the erythritol). compound taken from the group consisting of polymers 7. A composition of matter as in claim 1 wherein the 10 of ethylene and halogenated derivatives thereof. polyspirane resin comprises poly(3-methylglutardiylidene 14. The crosslinked insoluble reaction product of a pentaerythritol). polyspirane having the general formula 0-CH2 GET-0 0-011, CH -O-CH; GH -O leg goaloo j 3 ml i. 0-OH7 oni-o ix|' o-oni on, 0111 0132-0 J OH H Y 8. A composition of matter as in claim 1 wherein the polyspirane resin comprises poly(malondiylidene pentaerythritol) 9. A composition of matter as in claim 1 wherein the polyspirane resin comprises the copolymer of equimolar portions of glutaraldehyde and 3-methylglutaraldehyde with a mixture of 88 parts by Weight of monopentaerythn'tol and 12 parts of dipentaerythritol.

10. A composition of matter as in claim 1 wherein the polyspirane resin comprises poly(succindiylidene pentaerythritol) 11. A composition of matter comprising the crosslinked insoluble reaction product of a polyspirane resin having the general formula where R is taken from the group consisting of H and CH R is taken from the group consisting of aliphatic hydrocarbons defined by (CHQ where S is an integer from 0-8 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted products thereof, X plus Y is equal to an integer from 2-100 and Y is equal to no more than 50% of X plus Y, with an organic material selected from the group consisting of (a) polycarboxylic acid anhydrides of the saturated and unsaturated aliphatic series, (b) aromatic polycarboxylic acid anhydrides, (c) alicyclic polycarboxylic acid anhydrides, (d) methyl and halogen substituted products of (a), (b) and (c), (e) polymeric polyanhydrides selected from the class consisting of soluble copolymers of styrene-maleic anhydride and vinyl acetate-maleic anhydride, and (f) mixtures of (a), (b), (c), (d) and (e),

" l O-GH: CHr-O-CE:

CH O

where R is taken from the group consisting of H and CH R is taken from the group consisting of aliphatic hydrocarbons defined by (CI-I9 where S is an integer from 0-8 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted products thereof, X plus Y is equal to an integer from 2-100 and Y is equal to no more than 50% of X plus Y, a polyisocyanate and an organic material wherein the organic material is selected from the group consisting of (a) polycarboxylic acid anhydrides of the saturated and unsaturated aliphatic series, (b) aromatic polycarboxylic acid anhydrides, (c) alicyclic polycarboxylic acid anhydrides, (d) methyl and halogen substituted products of (a), (b) and (c), (e) polymeric polyanhydrides selected from the class consisting of soluble copolymers of styrene maleic anhydride and vinyl acetate-maleic anhydride and (1) mixtures of (a), (b), (c), (d) and (e).

15. A product as in claim 14 wherein the polyisocyanate is selected from the group consisting of polyisocyanates and blocked derivatives of polyisocyanates.

16. A product as in claim 14 wherein the polyisocyanate is the phenol adduct of the reaction product of 1 mol of trimethylolpropane and 3 mols of tolylene diisocyanate.

17. A product as in claim 14 comprising in parts by weight parts of the polyspirane, l-50 parts of the polyisocyanate, and 1-35 parts of the organic material.

18. The crosslinked reaction product of a polyspirane having the general formula om on, \CH20/ on on Y CH R is taken from the group consisting of aliphatic -where.R is taken from the group consisting of H and weight 100 parts of the polyspirane, 1-25 parts of the phenolic aldehyde resin, and l-35 parts of the organic material.

24. A process for the manufacture of a solid resinous product comprising the solution of a polyspirane resin having the general formula hydrocarbons defined by (CH where S is an integer from -8 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted products thereof, X plus Y is equal to an integer from O-OE: GHQ-4) O-CHz CHrOCH7 CH2-o o n /o\ R O-R CR /o o\ R OR L OCH2 0132-0 J31, OCH2 CHz C CHr-O J OH OH 2-100 and Y is equal to no more than 50% of X plus Y, .2,2-bis(p-hydroxyphenyl) propane-epichlorohydrin, epoxy resin and an organic material wherein the organic material is selected from'the group consisting of (a) polycarboxylic acid anhydrides of the saturated and unsaturated aliphatic series, (b) aromatic polycarboxylic products thereof, X plus Y is equal to an integer from acid anhydrides, (c) alicyclic polycarboxylic acid anhy- 2-100 and Yis. equal to no more than 50% of X plus Y, drides, (d) methyl and halogen substituted products of in a mixture of cresylic acid and a diluent therefor, there- (a), (b), and (c), (e) polymeric polyanhydrides selected after adding to the solution a soluble material selected from the class consisting of soluble copolymers of styrene from the group consisting of (I) (a) polycarboxylic acid maleic anhydride and vinyl acetate-maleic anhydride and anhydrides of the saturated and unsaturated aliphatic (f) mixtures of (a), (b), (c), (d) and (e). series, (b) aromatic polycarboxylic acid anhydrides,-(c)

19. A product as in claim 18 comprising in parts by alicyclic polycarboxylic acid anhydrides, (d) methyl and weight 100 parts of the polyspirane, 1-50 parts of the halogen substituted products of (a), (b) and (c), (e) epoxy resin, and 1-35 parts. of the organic material. polymeric anhydrides selected from the class consisting 0- A produc as in Claim 18 wherein the epoxy resin of soluble copolymers of styrene-maleic anhydride and portion has the general formula vinyl acetate-maleic anhydride and (f) mixtures of (a),

where R is taken from the group consisting of H and CH R is taken from the group consisting of aliphatic hydocarbons defined by (CH where S is an integer from 0-8 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted (b), (c), (d) and (e) and (II) (a) a material selected from (I) and a phenolic-aldehyde resin, (b) a material selected from (I) and a 2,2'-bis(p-hydroxyphenyl)propane-epichlorohydrin epoxy resin and (c) a material se- 40 lected from (I) and a polyisocyanate; finally removing H H C where X and Y are taken from the group consisting of hydrogen, methyl groups and aliphatic and aromatic hydrocarbons and N is an integer from 0 to 10.

21. The crosslinked insoluble reaction product of a polyspirane having the general formula o-orr on o-on on 0 ll 2- li 1i the solvent from the solution and heat curing the remainwhere R is taken from the group consisting of H and CH R is taken from the group consisting of aliphatic ing resin.

hydrocarbons defined by (CH where S is an integer 25. A coating composition comprising an organic solfrom 0-8 and alicyclic and aromatic hydrocarbons of vent solution of a polyspirane having the general formula 5-6 carbon atoms, and methyl and ethyl substituted prodwhere R is taken from the group consisting of H and ucts thereof, X plus Y is equal to an integer from 2-100 CH R is taken from the group consisting of aliphatic and Y is equal to 110 more than 50% of X P1118 Y, a hydrocarbons defined by (CH where S is an integer phenolicaldehyde resin and an Organic material 'F from 0-8 and alicyclic and aromatic hydrocarbons of 'f Orgamc matenrlal 1s S e1ecte d from h group conslst 5-6 carbon atoms, and methyl and ethyl substituted mg of g i i l aphydrgdes of h i products thereof, X plus Y is equal to an integer from rated unsiamrate i aromanc p0 Y 2-100 and Y is equal to no more than 50% of X plus Y, carboxyhc acid anhydride, (c) alicyclic polycarboxyhc and an organic material selected from the group conacld anhydrides, (d) methyl and halogen substituted prodsisting of (a) pdycarboxylic acid anhydride of the Sam b d h ucts of (e) polymenc polyan ydndes rated and unsaturated aliphatic series, (b) aromatic polyselected from the class consisting of soluble copolymers of styrene-maleic anhydride and vinyl acetate-maleic ancafboxyhc f anhydndes (c) ahcychc polycarboxylfc hydride, and (f) mixtures of (a), (b), (C), (d) and (6). acid anhydrioes, (d) methyl and halogen substituted acid 22. A product as in claim 21 wherein the phenolic Products of and Polymeric P aldehyde resin is the reaction product of 1 mol of the hydrides of soluble copolymers of Styrene-[1121166 yphenolic compound with 0.7 to 2.0 mols of formaldehyde. e and Vinyl acetate-1118160 anhydride and (f) 23. A product as in claim 21 comprising in parts by tnres of (a), (b), (c), (d) and (e).

26. Electrical insulation comprising the reaction prodanhydrides, (d) methyl and halogen substituted products uct of a polyspirane having the general formula of (a), (b) and (c), (e) polymeric polyanhydrides seo-CH, GHQ- 0-0H, CHz-O-CHg 0112-0 in C analog Rahal OH OH Y where R is taken from the group consisting of H and lected from the class consisting of soluble copolymers of CH R is taken from the group consisting of aliphatic styrene-maleic anhydride and vinyl acetate-maleic anhyhydrocarbons defined by (CH where S is an integer dride, and (f) mixtures of (a), (b), (c),v(d) and (e). from 0-8 and alicyclic and aromatic hydrocarbons of 28. A coated electrical conductor consisting of a bare 5-6 carbon atoms, and methyl and ethyl substituted prodmetal wire and a coating comprising the reaction products thereof, X plus Y is equal to an integer from 2-100 net of a polyspirane having the general formula and Y is equal to no more than 50% of X plus Y and where R is taken from the group consisting of H and an organic material selected from the group consisting of CH R is taken from the group consisting of aliphatic (a) polycarboxylic acid anhydrides of the saturated and hydrocarbons defined by (CH J where S is an integer unsaturated aliphatic series, (b) aromatic polycarboxylic from 0-8 and alicyclic and aromatic hydrocarbons of acid anhydrides, (c) alicyclic polycarboxylic acid anhy- 5-6 carbon atoms, and methyl and ethyl substituted proddrides, (d) methyl and halogen substituted products of nets thereof, X plus Y is equal to an integer from 2-100 (a), (b) and (c), (e) polymeric polyanhydrides selected and Y is equal to no more than 50% of X plus Y and from the class consisting of soluble copolymers of styrenean organic material selected from the group consisting maleic anhydride and vinyl acetate-maleic anhydride and of (a) poiycarboxylic acid anhyclrides of the saturated (1) mixtures of (a), (b), (c), (d), and (e). and unsaturated aliphatic series, (12) aromatic polycar- 27. An electrical conductor insulated with an organic boxylic acid anhydrides, (c) alicyclic polycarboxylic acid insulation comprising the reaction product of a polyanhydrides, (d) methyl and halogen substituted products spirane having the general formula of (a), (b), and (c), (e) polymeric polyanhydrides selo-om CH:O\ '1 I- /O-CH2 CHa-O-CE: CH:O\ -O R /C\ R;O-RC R R7C-R'- L O-GH: CH:O |x- O-CH: CH2 CH2 GHQ-O I H H Y where R is taken from the group consisting of H and 5 lected from the class consisting of soluble copolymers of CH R is taken from the group consisting of aliphatic styrene-maleic anhydride and vinyl acetate-maleic anhydrocarbons defined by (CH where S is an integer hydride, and (f) mixtures of (a), (b), (c), (a') and (e). from 0-8 and alicyclic and aromatic hydrocarbons of 5-6 carbon atoms, and methyl and ethyl substituted prod- References Cited in the m6 of this Pawnt ucts thereof, X plus Y is equal to an integer from 2-10() and Y is equal to no more than 50% of X plus Y and UNITED STATES PATENTS an organic material selected from the group consisting 2,643,236 Kropa et a1. June 23, 1953 of (a) polycarboxylic acid anhydrides of the saturated 2,739,972 Abbott etal Mar. 27,1956 and unsaturated aliphatic series, (b) aromatic polycar- 2,785,996 Kress et al. Mar. 19, 1957 boxylic acid anhydrides, (c) alicyclic polycarboxylic acid 2,895,945 Fischer et al. July 21, 1959 

18. THE CROSSLINKED REACTION PRODUCT OF A POLYSPIRANE HAVING THE GENERAL FORMULA 